Project Summary Early childhood caries (ECC), commonly referred to as tooth decay, is a preventable disease that disproportionally affects children enrolled in Medicaid and other historically disadvantaged groups. Receiving preventive oral health services (POHS) at an early age helps to prevent ECC, yet populations experiencing the most ECC have the lowest use of POHS. To improve access to POHS for these vulnerable populations, nearly all state Medicaid programs have adopted policies covering physician-based POHS. Despite widespread adoption of policies and evidence of policy effectiveness, states exhibit variation in rates of physician-based POHS use. This project will explore how physician-based POHS coverage policies have affected POHS use and oral health outcomes of Medicaid-enrolled infants and toddlers over time, overall, and among historically underserved and high-risk populations. Using a national sample, we will consider the reimbursement rate, training requirement, and comprehensiveness of services provided for physician-based POHS in order to identify the types of policies that best promote use of POHS and oral health outcomes.